SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                  SCHEDULE 13D

                    Under the Securities Exchange Act of 1934
                               (Amendment No. 2)*

                            LAMAR ADVERTISING COMPANY
                                (Name of Issuer)

                CLASS A COMMON STOCK, PAR VALUE $0.001 PER SHARE
                         (Title of Class of Securities)

                                    512815101
                                 (CUSIP Number)

                               SPO Advisory Corp.
                         591 Redwood Highway, Suite 3215
                          Mill Valley, California 94941
                                 (415) 383-6600

                                 with a copy to:

                                Alison S. Ressler
                             Sullivan & Cromwell LLP
                             1888 Century Park East
                       Los Angeles, California 90067-1725
                                 (310) 712-6600

           (Name, Address and Telephone Number of Person Authorized to
                       Receive Notices and Communications)

                                   JULY 17, 2006
             (Date of Event which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report
the acquisition that is the subject of this Schedule 13D, and is filing this
Schedule because of Rule 13d-1(e), 13d-1(f) or 13d-1(g), check the following
box |_|.

Note. Schedules filed in paper format shall include a signed original and five
copies of the schedule, including all exhibits. See Rule 13d-7 for other parties
to whom copies are to be sent.

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter
disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).

Page 1 of 25 Pages - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON SPO Partners II, L.P. - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) |_| (b) |X| - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS WC - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(e) OR 2(f) |_| - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION Delaware - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER 7,846,500 (1) ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By -0- Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER 7,846,500 (1) ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER -0- - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 7,846,500 (1) - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES |_| - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 8.96% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON PN - -------------------------------------------------------------------------------- (1) Power is exercised through its sole general partner, SPO Advisory Partners, L.P.

CUSIP No. 512815101 Page 2 of 25 Pages - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON SPO Advisory Partners, L.P. - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) |_| (b) |X| - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS Not Applicable - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(e) OR 2(f) |_| - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION Delaware - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER 7,846,500 (1)(2) ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By -0- Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER 7,846,500 (1)(2) ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER -0- - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 7,846,500 (1)(2) - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES |_| - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 8.96% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON PN - -------------------------------------------------------------------------------- (1) Solely in its capacity as the sole general partner of SPO Partners II, L.P. (2) Power is exercised through its sole general partner, SPO Advisory Corp.

CUSIP No. 512815101 Page 3 of 25 Pages - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON San Francisco Partners II, L.P. - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) |_| (b) |X| - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS WC - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(e) OR 2(f) |_| - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION California - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER 404,130 (1) ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By -0- Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER 404,130 (1) ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER -0- - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 404,130 (1) - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES |_| - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.46% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON PN - -------------------------------------------------------------------------------- (1) Power is exercised through its sole general partner, SF Advisory Partners, L.P.

CUSIP No. 512815101 Page 4 of 25 Pages - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON SF Advisory Partners, L.P. - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) |_| (b) |X| - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS Not Applicable - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(e) OR 2(f) |_| - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION Delaware - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER 404,130 (1)(2) ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By -0- Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER 404,130 (1)(2) ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER -0- - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 404,130 (1)(2) - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES |_| - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.46% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON PN - -------------------------------------------------------------------------------- (1) Solely in its capacity as the sole general partner of San Francisco Partners II, L.P. (2) Power is exercised through its sole general partner, SPO Advisory Corp.

CUSIP No. 512815101 Page 5 of 25 Pages - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON SPO Advisory Corp. - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) |_| (b) |X| - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS Not Applicable - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(e) OR 2(f) |_| - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION Delaware - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER 8,250,630 (1)(2) ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By -0- Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER 8,250,630 (1)(2) ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER -0- - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 8,250,630 (1)(2) - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES |_| - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 9.42% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON CO - -------------------------------------------------------------------------------- (1) Solely in its capacity as the sole general partner of SPO Advisory Partners, L.P. with respect to 7,846,500 of such shares; and solely in its capacity as the sole general partner of SF Advisory Partners, L.P. with respect to 404,130 of such shares. (2) Power is exercised through its three controlling persons, John H. Scully, William E. Oberndorf and William J. Patterson.

CUSIP No. 512815101 Page 6 of 25 Pages - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON John Scully - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) |_| (b) |X| - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS Not Applicable - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(e) OR 2(f) |_| - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION USA - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER -0- ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By 8,250,630 (1) Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER -0- ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER 8,250,630 (1) - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 8,250,630 (1) - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES |_| - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 9.42% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON IN - -------------------------------------------------------------------------------- (1) These shares may be deemed to be beneficially owned by Mr. Scully solely in his capacity as one of three controlling persons of SPO Advisory Corp.

CUSIP No. 512815101 Page 7 of 25 Pages - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON William E. Oberndorf - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) |_| (b) |X| - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS Not Applicable - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(e) OR 2(f) |_| - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION USA - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER -0- ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By 8,250,630 (1) Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER -0- ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER 8,250,630 (1) - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 8,250,630 (1) - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES |_| - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 9.42% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON IN - -------------------------------------------------------------------------------- (1) These shares may be deemed to be beneficially owned by Mr. Oberndorf solely in his capacity as one of three controlling persons of SPO Advisory Corp.

CUSIP No. 512815101 Page 8 of 25 Pages - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON William J. Patterson - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) |_| (b) |X| - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS Not Applicable - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(e) OR 2(f) |_| - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION USA - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER -0- ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By 8,250,630 (1) Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER -0- ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER 8,250,630 (1) - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 8,250,630 (1) - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES |_| - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 9.42% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON IN - -------------------------------------------------------------------------------- (1) These shares may be deemed to be beneficially owned by Mr. Patterson solely in his capacity as one of three controlling persons of SPO Advisory Corp.

Page 9 of 25 Pages This Amendment No. 2 amends the Schedule 13D (the "Original 13D") filed with the Securities and Exchange Commission ("SEC") on August 22, 2005 and as amended on May 10, 2006. Unless otherwise stated herein, the Original 13D, as previously amended, remains in full force and effect. Terms used therein and not defined herein shall have the meanings ascribed thereto in the Original 13D. ITEM 3. SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION. Item 3 is hereby amended and restated in its entirety as follows: The source and amount of the funds used or to be used by the Reporting Persons to purchase Shares are as follows: NAME SOURCE OF FUNDS AMOUNT OF FUNDS - --------------------- --------------------------- --------------- SPO Contributions from Partners $352,404,764 SPO Advisory Partners Not Applicable Not Applicable SFP Contributions from Partners $16,946,284 SF Advisory Partners Not Applicable Not Applicable SPO Advisory Corp. Not Applicable Not Applicable JHS Not Applicable Not Applicable WEO Not Applicable Not Applicable WJP Not Applicable Not Applicable ITEM 5. INTEREST IN SECURITIES OF THE ISSUER. (a) Percentage interest calculations for each Reporting Person are based upon the Issuer having 87,604,773 total outstanding shares of Class A common stock as reported on the Issuer's 10-Q filed with the Securities and Exchange Commission on May 10, 2006. SPO The aggregate number of Shares that SPO owns beneficially, pursuant to Rule 13d-3 of the Act, is 7,846,500 Shares, which constitutes approximately 8.96% of the outstanding Shares. SPO Advisory Partners Because of its position as the sole general partner of SPO, SPO Advisory Partners may, pursuant to Rule 13d-3 of the Act, be deemed to be the beneficial owner of 7,846,500 Shares, which constitutes approximately 8.96% of the outstanding Shares. SFP The aggregate number of Shares that SFP owns beneficially, pursuant to Rule 13d-3 of the Act, is 404,130 Shares, which constitutes approximately 0.46% of the outstanding Shares.

Page 10 of 25 Pages SF Advisory Partners Because of its position as the sole general partner of SFP, SF Advisory Partners may, pursuant to Rule 13d-3 of the Act, be deemed to be the beneficial owner of 404,130 Shares, which constitutes approximately 0.46% of the outstanding Shares. SPO Advisory Corp. Because of its positions as the sole general partner of each of SPO Advisory Partners and SF Advisory Partners, SPO Advisory Corp. may, pursuant to Rule 13d-3 of the Act, be deemed to be the beneficial owner of 8,250,630 Shares in the aggregate, which constitutes approximately 9.42% of the outstanding Shares. JHS Because of his position as a control person of SPO Advisory Corp., JHS may, pursuant to Rule 13d-3 of the Act, be deemed to be the beneficial owner of 8,250,630 Shares, which constitutes approximately 9.42% of the outstanding Shares. WEO Because of his position as a control person of SPO Advisory Corp., WEO may, pursuant to Rule 13d-3 of the Act, be deemed to be the beneficial owner of 8,250,630 Shares, which constitutes approximately 9.42% of the outstanding Shares. WJP Because of his position as a control person of SPO Advisory Corp., WJP may, pursuant to Rule 13d-3 of the Act, be deemed to be the beneficial owner of 8,250,630 Shares, which constitutes approximately 9.42% of the outstanding Shares. To the best of the knowledge of each of the Reporting Persons, other than as set forth above, none of the persons named in Item 2 hereof is the beneficial owner of any Shares. (b) SPO Acting through its sole general partner, SPO has the sole power to vote or to direct the vote and to dispose or to direct the disposition of 7,846,500 Shares. SPO Advisory Partners Acting through its sole general partner and in its capacity as the sole general partner of SPO, SPO Advisory Partners has the sole power to vote or to direct the vote and to dispose or to direct the disposition of 7,846,500 Shares. SFP Acting through its sole general partner, SFP has the sole power to vote or to direct the vote and to dispose or to direct the disposition of 404,130 Shares.

Page 11 of 25 Pages SF Advisory Partners Acting through its sole general partner and in its capacity as the sole general partner of SFP, SF Advisory Partners has the sole power to vote or to direct the vote and to dispose or to direct the disposition of 404,130 Shares. SPO Advisory Corp. Acting through its controlling persons and in its capacities as the sole general partner of each of SPO Advisory Partners and SF Advisory Partners, SPO Advisory Corp. has the sole power to vote or to direct the vote and to dispose or to direct the disposition of 8,250,630 Shares in the aggregate. JHS As one of three controlling persons of SPO Advisory Corp., which is the sole general partner of each of SPO Advisory Partners and SF Advisory Partners, JHS may be deemed to have shared power with WEO and WJP to vote or to direct the vote and to dispose or to direct the disposition of 8,250,630 Shares held by SPO and SFP in the aggregate. WEO As one of three controlling persons of SPO Advisory Corp., which is the sole general partner of each of SPO Advisory Partners and SF Advisory Partners, WEO may be deemed to have shared power with JHS and WJP to vote or to direct the vote and to dispose or to direct the disposition of 8,250,630 Shares held by SPO and SFP in the aggregate. WJP As one of three controlling persons of SPO Advisory Corp., which is the sole general partner of each of SPO Advisory Partners and SF Advisory Partners, WJP may be deemed to have shared power with JHS and WEO to vote or to direct the vote and to dispose or to direct the disposition of 8,250,630 Shares held by SPO and SFP in the aggregate. (c) Within the past 60 days of the date of this statement, Reporting Persons purchased Shares in open market transactions on the Nasdaq National Market as set forth on Schedule I attached hereto. Except as set forth in this paragraph (c), to the best of the knowledge of each of the Reporting Persons, none of the persons named in response to paragraph (a) has effected any transactions in Shares during the past 60 days. (d) Each of the Reporting Persons affirms that no person other than such Reporting Person has the right to receive or the power to direct the receipt of distributions with respect to, or the proceeds from the sale of, Shares owned by such Reporting Person. (e) Not applicable. ITEM 7. MATERIAL TO BE FILED AS EXHIBITS. Item 7 is hereby amended and restated in its entirety as follows: Exhibit A: Agreement pursuant to Rule 13d-1 (k)

Page 12 of 25 Pages SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. Dated July 19, 2006 By: /s/ Kim M. Silva -------------------------------- Kim M. Silva Attorney-in-Fact for: SPO PARTNERS II, L.P.(1) SPO ADVISORY PARTNERS, L.P.(1) SAN FRANCISCO PARTNERS II, L.P.(1) SF ADVISORY PARTNERS, L.P.(1) SPO ADVISORY CORP.(1) JOHN H. SCULLY(1) WILLIAM E. OBERNDORF(1) WILLIAM J. PATTERSON(1) (1) A Power of Attorney authorizing Kim M. Silva to act on behalf of this person or entity has been previously filed with the Securities and Exchange Commission.

Page 13 of 25 Pages SCHEDULE I TO SCHEDULE 13D FOR SPO PARTNERS II, L.P. DATE OF NUMBER OF PRICE PER WHERE/HOW REPORTING PERSON TRANSACTION TYPE SHARES SHARE ($) TRANSACTION EFFECTED - --------------------------- ----------- ---- --------- --------- -------------------- SPO Partners II, L.P. 5/30/2006 Buy 4,402 54.7246 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 1,693 54.7259 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 2,950 54.72745 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 4,158 54.72753 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 19,948 54.7300 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 5,000 54.7304 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 4,287 54.7367 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 50,000 54.7435 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 4,984 54.7445 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 29,179 54.7500 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 1,362 54.7551 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 600 54.7567 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 230 54.7587 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 3,443 54.7591 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 1,507 54.7600 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 1,681 54.7686 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 1,273 54.7700 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 1,943 54.7704 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 2,649 54.7706 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 5,000 54.7724 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 1,340 54.7900 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 1,028 54.7915 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 1,455 54.7938 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 4,300 54.7963 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 508 54.7987 Open Market/Broker

Page 14 of 25 Pages SCHEDULE I TO SCHEDULE 13D FOR SPO PARTNERS II, L.P. DATE OF NUMBER OF PRICE PER WHERE/HOW REPORTING PERSON TRANSACTION TYPE SHARES SHARE ($) TRANSACTION EFFECTED - --------------------------- ----------- ---- --------- --------- -------------------- SPO Partners II, L.P. 5/30/2006 Buy 630 54.7994 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 4,980 54.8000 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 2,644 54.8030 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 4,704 54.8055 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 2,645 54.8096 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 4,102 54.8098 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 1,885 54.8188 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 1,154 54.8222 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 5,000 54.8246 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 1,290 54.8255 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 78 54.8300 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 3,287 54.8397 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 4,410 54.8486 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 3,316 54.8496 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 45,185 54.8500 Open Market/Broker SPO Partners II, L.P. 5/30/2006 Buy 4,770 54.8548 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 1,300 54.6500 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 98 54.6700 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 200 54.7000 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 900 54.7100 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 400 54.7300 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 1,302 54.7400 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 1,500 54.7500 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 1,100 54.7600 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 303 54.7700 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 100 54.7760 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 700 54.7800 Open Market/Broker

Page 15 of 25 Pages SCHEDULE I TO SCHEDULE 13D FOR SPO PARTNERS II, L.P. DATE OF NUMBER OF PRICE PER WHERE/HOW REPORTING PERSON TRANSACTION TYPE SHARES SHARE ($) TRANSACTION EFFECTED - --------------------------- ----------- ---- --------- --------- -------------------- SPO Partners II, L.P. 5/31/2006 Buy 1,400 54.7900 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 100 54.7969 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 32,297 54.8000 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 100 54.8033 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 1,500 54.8200 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 400 54.8300 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 900 54.8500 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 800 54.8600 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 576 54.8700 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 300 54.8800 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 100 54.8804 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 1,800 54.8900 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 624 54.9000 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 700 54.9100 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 200 54.9200 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 200 54.9400 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 500 54.9700 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 1,000 54.9800 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 100 54.9900 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 1,100 55.0000 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 500 55.0200 Open Market/Broker SPO Partners II, L.P. 5/31/2006 Buy 1,900 55.0500 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 5,000 50.3455 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 10,000 50.3567 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 5,000 50.3688 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 7,500 50.3811 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 5,000 50.4912 Open Market/Broker

Page 16 of 25 Pages SCHEDULE I TO SCHEDULE 13D FOR SPO PARTNERS II, L.P. DATE OF NUMBER OF PRICE PER WHERE/HOW REPORTING PERSON TRANSACTION TYPE SHARES SHARE ($) TRANSACTION EFFECTED - --------------------------- ----------- ---- --------- --------- -------------------- SPO Partners II, L.P. 6/13/2006 Buy 7,500 50.5611 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 7,000 50.6110 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 5,000 50.6226 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 5,500 50.6926 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 7,500 50.6945 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 5,000 50.7000 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 5,000 50.7465 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 5,000 50.8536 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 7,000 50.8678 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 5,500 50.9137 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 7,500 50.9652 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 5,000 51.2015 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 20,000 51.2079 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 5,000 51.2211 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 15,000 51.2386 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 10,000 51.2500 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 5,000 51.2955 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 5,000 51.4700 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 5,000 51.4800 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 5,000 51.4900 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 5,000 51.6000 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 40,000 51.6900 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 10,000 51.7391 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 5,000 51.7700 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 75,000 51.7900 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 5,000 51.8800 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 25,000 51.9000 Open Market/Broker

Page 17 of 25 Pages SCHEDULE I TO SCHEDULE 13D FOR SPO PARTNERS II, L.P. DATE OF NUMBER OF PRICE PER WHERE/HOW REPORTING PERSON TRANSACTION TYPE SHARES SHARE ($) TRANSACTION EFFECTED - --------------------------- ----------- ---- --------- --------- -------------------- SPO Partners II, L.P. 6/13/2006 Buy 10,000 51.9100 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 15,000 51.9300 Open Market/Broker SPO Partners II, L.P. 6/13/2006 Buy 10,000 51.9400 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 6,592 50.6000 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 100 50.6100 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 500 50.6180 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 14 50.6200 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 800 50.6262 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 200 50.6300 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 3,488 50.6400 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 10,105 50.6500 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 400 50.6525 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 1,300 50.6600 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 400 50.6650 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 2,700 50.6700 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 500 50.6740 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 300 50.6767 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 2,383 50.6800 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 200 50.6850 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 1,300 50.6900 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 300 50.6933 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 2,518 50.7000 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 1,500 50.7100 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 300 50.7133 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 900 50.7200 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 700 50.7243 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 200 50.7250 Open Market/Broker

Page 18 of 25 Pages SCHEDULE I TO SCHEDULE 13D FOR SPO PARTNERS II, L.P. DATE OF NUMBER OF PRICE PER WHERE/HOW REPORTING PERSON TRANSACTION TYPE SHARES SHARE ($) TRANSACTION EFFECTED - --------------------------- ----------- ---- --------- --------- -------------------- SPO Partners II, L.P. 7/17/2006 Buy 2,000 50.7400 Open Market/Broker SPO Partners II, L.P. 7/17/2006 Buy 300 50.7500 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,214 50.1025 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 400 50.1200 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,000 50.1400 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,000 50.1530 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.1867 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 700 50.1871 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 500 50.2140 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 200 50.2200 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 200 50.2350 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 700 50.2386 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 500 50.2480 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 200 50.2600 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,100 50.2791 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 100 50.2800 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.2933 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 400 50.2975 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 900 50.3000 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 700 50.3071 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 447 50.3100 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.3167 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 400 50.3175 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,000 50.3200 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,000 50.3240 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,206 50.3300 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 600 50.3333 Open Market/Broker

Page 19 of 25 Pages SCHEDULE I TO SCHEDULE 13D FOR SPO PARTNERS II, L.P. DATE OF NUMBER OF PRICE PER WHERE/HOW REPORTING PERSON TRANSACTION TYPE SHARES SHARE ($) TRANSACTION EFFECTED - --------------------------- ----------- ---- --------- --------- -------------------- SPO Partners II, L.P. 7/18/2006 Buy 100 50.3357 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 200 50.3400 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 500 50.3440 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.3467 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 2,303 50.3483 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 6,032 50.3500 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 200 50.3517 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 200 50.3584 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,200 50.3600 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,700 50.3616 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,800 50.3700 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 700 50.3714 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 500 50.3740 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 400 50.3750 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 100 50.3766 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 400 50.3775 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 5,577 50.3800 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 800 50.3850 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 500 50.3860 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 6,567 50.3900 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.3933 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 700 50.3943 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 200 50.3950 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 700 50.3957 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 827 50.3960 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,200 50.3975 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 3,441 50.4000 Open Market/Broker

Page 20 of 25 Pages SCHEDULE I TO SCHEDULE 13D FOR SPO PARTNERS II, L.P. DATE OF NUMBER OF PRICE PER WHERE/HOW REPORTING PERSON TRANSACTION TYPE SHARES SHARE ($) TRANSACTION EFFECTED - --------------------------- ----------- ---- --------- --------- -------------------- SPO Partners II, L.P. 7/18/2006 Buy 200 50.4050 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 4,835 50.4100 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 800 50.4125 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,603 50.4200 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 600 50.4287 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 2,600 50.4300 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 200 50.4350 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 4,896 50.4400 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 600 50.4401 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 400 50.4425 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 400 50.4450 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 600 50.4467 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 3,204 50.4500 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 600 50.4567 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 10,008 50.4600 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 600 50.4617 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 200 50.4650 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 2,782 50.4700 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 500 50.4720 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 500 50.4740 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 600 50.4750 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 7,518 50.4800 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 200 50.4850 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 500 50.4860 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 600 50.4867 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 12,849 50.4900 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 400 50.4925 Open Market/Broker

Page 21 of 25 Pages SCHEDULE I TO SCHEDULE 13D FOR SPO PARTNERS II, L.P. DATE OF NUMBER OF PRICE PER WHERE/HOW REPORTING PERSON TRANSACTION TYPE SHARES SHARE ($) TRANSACTION EFFECTED - --------------------------- ----------- ---- --------- --------- -------------------- SPO Partners II, L.P. 7/18/2006 Buy 900 50.4933 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 600 50.4950 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 800 50.4952 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.4967 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 100 50.4970 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 400 50.4975 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 500 50.4980 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 77,812 50.5000 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,000 50.5020 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 400 50.5025 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 500 50.5060 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 600 50.5067 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.5081 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 19,972 50.5100 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 700 50.5114 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 400 50.5150 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 900 50.5167 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 400 50.5175 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,800 50.5178 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,000 50.5180 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 25,979 50.5200 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 400 50.5225 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 600 50.5233 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,700 50.5234 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 200 50.5250 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.5267 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 12,713 50.5300 Open Market/Broker

Page 22 of 25 Pages SCHEDULE I TO SCHEDULE 13D FOR SPO PARTNERS II, L.P. DATE OF NUMBER OF PRICE PER WHERE/HOW REPORTING PERSON TRANSACTION TYPE SHARES SHARE ($) TRANSACTION EFFECTED - --------------------------- ----------- ---- --------- --------- -------------------- SPO Partners II, L.P. 7/18/2006 Buy 500 50.5320 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.5333 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 400 50.5350 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 700 50.5371 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 200 50.5386 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,200 50.5390 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 13,334 50.5400 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 700 50.5414 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 52,442 50.5500 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,800 50.5502 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,200 50.5550 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.5567 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 200 50.5575 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 4,000 50.5600 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.5633 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,700 50.5653 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 500 50.5680 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 8,690 50.5700 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 4,500 50.5800 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 900 50.5844 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,303 50.5900 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 649 50.5903 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 8,588 50.6000 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,500 50.6020 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 3,000 50.6030 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 200 50.6050 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 700 50.6100 Open Market/Broker

Page 23 of 25 Pages SCHEDULE I TO SCHEDULE 13D FOR SPO PARTNERS II, L.P. DATE OF NUMBER OF PRICE PER WHERE/HOW REPORTING PERSON TRANSACTION TYPE SHARES SHARE ($) TRANSACTION EFFECTED - --------------------------- ----------- ---- --------- --------- -------------------- SPO Partners II, L.P. 7/18/2006 Buy 400 50.6140 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 600 50.6200 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.6267 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 96 50.6300 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,451 50.6400 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 3,400 50.6500 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,500 50.6600 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,104 50.6700 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,100 50.6800 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 500 50.6900 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.6933 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 4,715 50.7000 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 2,203 50.7100 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 700 50.7200 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 664 50.7300 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.7333 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 576 50.7400 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.7500 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 600 50.7600 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 700 50.7657 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 600 50.7667 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 200 50.7700 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 500 50.7760 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 100 50.7800 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.7905 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.8033 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.8171 Open Market/Broker

Page 24 of 25 Pages SCHEDULE I TO SCHEDULE 13D FOR SPO PARTNERS II, L.P. DATE OF NUMBER OF PRICE PER WHERE/HOW REPORTING PERSON TRANSACTION TYPE SHARES SHARE ($) TRANSACTION EFFECTED - --------------------------- ----------- ---- --------- --------- -------------------- SPO Partners II, L.P. 7/18/2006 Buy 400 50.8550 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 100 50.8600 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 200 50.8900 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.9148 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 100 50.9400 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 300 50.9500 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 1,000 50.9530 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 900 51.0000 Open Market/Broker SPO Partners II, L.P. 7/18/2006 Buy 200 51.0250 Open Market/Broker

Page 25 of 25 Pages EXHIBIT INDEX EXHIBIT DOCUMENT DESCRIPTION PAGE NO. - ------- -------------------- -------- A Agreement Pursuant to Rule 13d-1 (k) 1

                                    EXHIBIT A

         Pursuant to Rule 13d-1(k) of Regulation 13D-G of the General Rules and
Regulations of the Securities and Exchange Commission under the Securities
Exchange Act of 1934, as amended, the undersigned agrees that the statement to
which this Exhibit is attached is filed on behalf of each of them in the
capacities set forth below.

Dated:  July 19, 2006

                                         By: /s/ Kim M. Silva
                                             --------------------------
                                             Kim M. Silva

                                         Attorney-in-Fact for:

                                         SPO PARTNERS II, L.P.(1)
                                         SPO ADVISORY PARTNERS, L.P.(1)
                                         SAN FRANCISCO PARTNERS II, L.P.(1)
                                         SF ADVISORY PARTNERS, L.P.(1)
                                         SPO ADVISORY CORP.(1)
                                         JOHN H. SCULLY(1)
                                         WILLIAM E. OBERNDORF(1)
                                         WILLIAM J. PATTERSON(1)

                                         (1) A Power of Attorney
                                         authorizing Kim M. Silva to
                                         act on behalf of this
                                         person or entity has been
                                         previously filed with the
                                         Securities and Exchange
                                         Commission.